unable to read composite types from CSV files

Hello,

I am initializing tables with data imported/read from CSV files. This is
working well except for those tables that contain composite types.

When attempting to import/read CSV files containing composite data then the
error message I get is: ERROR: extra data after last expected column. My
questions are a follow:

1) Can composite types be imported from CSV files? Or can the CSV file
only contain base types (e.g. text, integer, real)? If composite types
CANNNOT be imported from CSV files then please let me know - in this case
you can ignore the remainder of this post.

2) If composite types can indeed be read/imported from CSV files then
would you please take a look at the sample code/data provided below and tell
me why it generates the error message 'extra data after last expected
column'. In other words, what am I doing wrong?

BTW, if I remove the parenthesis in the CSV file, read each field separately
into a temporary table then I can successfully copy the contents of the
temporary table into the 'permanent' table. However, it would be much more
convenient to read composite types directly from the CSV file and avoid
working with temporary tables.

I am working with PostgreSQL 10.3 (compiled by Visual C++ build 1800,
64-bit) running under Windows 10 64 bit. I am using NotePad++ as an editor.
The sample code is run in PSQL.

SQL Test code

The test code I am running in PSQL is as follows:

\! cls

\c postgres;

drop database if exists TestDB;

create database TestDB

with

owner = postgres

encoding = 'UTF8'

LC_COLLATE = 'English_United States.1252'

LC_CTYPE = 'English_United States.1252'

tablespace = pg_default

connection limit = -1;

\connect testdb;

create schema Test;

create type Test.MyType as(

X int,

Y int,

Z int

);

create table Test.A(

id serial not null primary key,

MT1 Test.MyType

);

\copy Test.A( MT1 ) from './testComposite.csv' with CSV DELIMITER ',';

Test CSV file contents

The contents of the CSV file (i.e. 'testComposite.csv') is:

(1,2,3)

(4,5,6)

(7,8,9)

Error Message

The error message I get is as follows:

psql:testComposite.sql:42: ERROR: extra data after last expected column

CONTEXT: COPY a, line 1: "(1, 2, 3)"